# Can you set a font at 11,5?

I tried `\documentclass[11,5pt]{book}`, but received `LaTeX Warning: Unused global option(s): [11,5pt].`

• As a note: `scrbook` would allow arbitrary font sizes with `\documentclass[fontsize=11.5pt]{scrbook}`. Note however that you need a scalable font in order to use arbitraty font sizes (either way). – Skillmon Nov 21 '17 at 20:16

You can use a font of that size `\fontsize{11.5}{12}\selectfont` but the options to book are not lengths they are just names of options and there are just three that look a bit like lengths: 10pt, 11pt, 12pt, and they do a lot more than set a font size they set the page size, the size of all the named sizes etc.

• I'm getting plenty of `LaTeX Font Warning: Font shape OT1/cmr/m/n' in size <11.5> not available (Font) size <12> substituted on input line 156.` I think I'll settle for 12pt finally. My fonts dont support it as Skillmon said – alfred Nov 21 '17 at 20:24
• add `\RequirePackage{fix-cm}` @alfred It is rather unlikely that you are not using scalable fonts. – David Carlisle Nov 21 '17 at 20:52
• @DavidCarlisle Why `RequirePackage`? alfred isn't writing a class. `usepackage` is the convention for user documents, isn't it? – JAB Nov 22 '17 at 4:05
• @JAB: The fix-cm documentation says to load it before `\documentclass` and using `\RequirePackage`, because "If the package is loaded in the preamble, a preceding package or even the code of the document class may have used any of the CM fonts already. However, the definitions of those fonts, that are already in use, cannot be changed any more." – Nick Matteo Nov 22 '17 at 4:29
1. Not all parsers understand 11,5 (with comma) to mean 11.5 (with period). EDIT: In general, it is a matter of choosing a language setting.

2. If your book is general writing (not math), consider the "novel" document class. Since it uses LuaLaTeX with fontspec, you can easily choose a decimal font size using Open Type fonts.

• (1) seems false or at least confusing, parsers of other languages may or may not allow a decimal comma depending on the language, but surely any tex parser will be able to parse tex. and so `\fontsize{11,5}{12,5}` – David Carlisle Nov 22 '17 at 7:34
• @DavidCarlisle Agreed that my comment was unclear. – user139954 Nov 22 '17 at 15:44
• You can edit it:-) – David Carlisle Nov 22 '17 at 15:56